Single-wall carbon nanotubes (SWNTs) have unique structural, electronic and mechanical properties that make them appealing for a variety of applications [Ijima et al., Nature, 363, 603-605, 1993; Lansbury et al., J. Am. Chem. Soc., 120, 603-604, 1998; Yu et al., Phys. Rev. Lett., 84, 5552-5555, 2000; Baughman et al., Science, 297, 787-792, 2002; Odom et al., J. Phys. Chem. B 104, 2794-2809, 2000; Kong et al., Science 287, 622-625, 1998; Rao et al., ChemPhysChem, 2, 78-105, 2001; Gao et al., Adv. Mater., 13, 1770-1773, 2001]. For instance, the remarkable tensile strength of SWNTs has led to the fabrication of a variety of nanotube-reinforced fibers and composite materials [Calvert, Nature, 399, 210-211, 1999; Gong et al., Chem. Mater., 12, 1049-1052, 2000; Yudasaka et al., Appl. Phys. A, 71, 449-451, 2000; Vigolo et al., Science, 290, 1331-1334, 2000; Coleman et al., Adv. Mater., 12, 213-216, 2000]. However, a major barrier to fully exploiting the unique properties of SWNTs exists, especially in the area of nanotube-reinforced fibers and composites. As processing and manipulation techniques for making such nanotube composites generally rely on dispersion and solubilization of the SWNTs, the nanotubes' inherent insolubility in water and most common organic solvents presents a problem.
In order to overcome this problem by producing soluble SWNT samples, work continues to evolve in the areas of non-covalent surfactant [Chen et al., J. Am. Chem. Soc., 123, 3838-3839, 2001; Jin et al., Chem. Phys. Lett., 332, 461-466, 2000] or polymer wrapping [O'Connell et al., Chem. Phys. Lett., 342, 265-271, 2001; Star et al., Angew. Chem. Int. Ed., 40, 1721-1725, 2001; Dalton et al., J. Phys. Chem. B, 104, 10012-10016, 2000; Tang et al., Macromolecules, 32, 2569-2576, 1999] modification of SWNTs, as well as on covalent functionalization [Bahr et al., J. Mater. Chem., 12, 1952-1958, 2002 (“Bahr I”); Khabashesku et al., Acc. Chem. Res., 35, 1087-1095, 2002 (“Khabashesku”)] utilizing both the open end [Chen et al., Science, 282, 95-98, 1998; Liu et al., Science, 280, 1253-1256, 1998 (“Liu”); Hamon et al., Adv. Mater., 11, 834-840, 1999; Riggs et al., J. Am. Chem. Soc., 122, 5879-5880, 2000; Sun et al., Chem. Mater., 13, 2864-2869, 2001] and sidewall [Mickelson et al., Chem. Phys. Lett. 296, 188-194, 1998 (“Mickelson I”); Mickelson et al., J. Phys. Chem. B 103, 4318-4322, 1999 (“Mickelson II”); Boul et al., Chem. Phys. Lett. 310, 367-372, 1999; Pekker et al., J. Phys. Chem. B, 105, 7938-7943, 2001 (“Pekker”); Bahr et al., J. Am. Chem. Soc. 123, 6536-6542, 2001 (“Bahr II”); Bahr et al., Chem. Mater. 13, 3823-3824, 2001 (“Bahr III”); Holzinger et al., Angew. Chem. Int. Ed. 40, 4002-4005, 2001 (“Holzinger”)] chemistry of SWNTs. Besides the general improvement in the solubility and processibility achieved by these approaches, the sidewall functionalizations, in particular, provide the most significant alteration of the structural and electronic properties of the SWNTs—yielding new nanotube derivatives with useful properties of their own. The direct addition of fluorine [Mickelson I; Mickelson II], hydrogen [Pekker], aryl groups [Bahr II; Bahr III], nitrenes, carbenes, and radicals [Holzinger; Peng et al., Chem. Comm., 362, 2003], as well as 1,3-dipolar and electrophilic additions [Georgakilas et al., J. Am. Chem. Soc. 124, 760-761, 2001; Tagmatarchis et al., Chem. Commun. 2010, 2002], to the side walls of pristine SWNTs have been reported. In the earliest reports on sidewall functionalization chemistry [Mickelson I; Mickelson II], it was shown that fluorine substituents on SWNTs (i.e., fluorinated SWNTs or fluoronanotubes) can be readily displaced by alkyl groups using Grignard or alkyllithium reagents which attach alkyl groups to the SWNT sidewalls through C—C bonds. These reactions are facilitated by C—F bonds on the fluoronanotube that are weaker than the C—F bonds in alkylfluorides, and which impart stronger electron accepting ability to the fluoronanotubes in comparison to pristine SWNTs [Bettinger et al., J. Am. Chem. Soc. 123, 12849-12856, 2001]. Such enhanced reactivity of fluoronanotubes opens opportunities for sidewall attachment of a variety of substituents. For instance, nanotubes comprising terminal amino- or hydroxyl-functional groups can be useful for further chemical modifications, were such species readily synthesizable.